1. Field of the Invention
The invention relates to a method of producing chemical adhesion between moldable compounds based on polyesters and EP(D)M rubbers containing carboxyl groups, and to composite or bonded materials thereby produced.
2. Description of the Background
In many cases, not all the properties desired in a given product can be contributed by a single material. Such inconsistent combinations of properties are, e.g., strength along with rubber-like elasticity, or high hardness and rigidity along with non-skid properties (traction).
Composite materials comprised of rigid thermoplastic moldable compounds and rubber-like elastic molding compounds are customarily held together by adhesive bonding, screwing, riveting, or mechanical coupling by form-interlocking means. Recently, interesting methods have been developed for producing direct chemical adhesion between certain rubbers and molding compounds based on polyphenylene ethers (PPEs) (see German OS 36 02 705, and German Patent App. P 37 39 891.0).
The adhesion values achieved are substantial. Now that means are available for producing such composite or bonded materials, it would be desirable to also produce composites or bonded materials, the thermoplastic component of which has not only high shape retention when heated, but also good solvent resistance, good weatherability, and outstanding sliding friction properties.
It should be mentioned that unpublished German Patent App. P 38 18 151.7 teaches a method of producing direct chemical adhesion between aliphatic polyamides and rubbers which contain carboxyl groups. This bonded system is distinguished by solvent resistance and weatherability.
Although it is known that the method referred to above is tied to certain critical parameters, basically it is possibly conceivable to replace the PPEs with other thermoplastics which are known to better satisfy the requirements described above. However, even though certain materials, e.g. polyesters, may be known to satisfy these requirements, under the process conditions recognized as essential, they do not produce sufficient adhesion (see Comparison Examples, infra). Accordingly, based on the state of the art, it did not seem possible to produce direct chemical adhesion between thermoplastic polyesters and rubbers, a need for which continues to exist.